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By H. F. Silliman, Daniel R. Hull, John R. Freeman

In the normal operation of a brass-rolling mill, sheet and strip has, for the most part, been finished in comparatively thin gauges, involving a substantial amount of cold-work and a considerable number of anneals. This condition has been disturbed by the preponderance of cartridge brass, which is not rolled to thin gauges, and particularly by brass for artillery cartridge cases, on which the mill may finish its work at a thickness between 0.400 and 0.900 in. Obviously, the amount of rolling and the number of anneals to which such a product can be subjected are small compared with strip that is carried to a thickness of a few hundredths of an inch. As a result, critical examination into the internal condition of metal has been made on an extensive scale at a stage of manufacture that would not, in normal times, have been chosen for complete inspection. Under these conditions, a type of defect has been recognized that is not seen at thinner gauges. It might be more accurate to call it the appearance of a defect, since it refers to an apparently laminated, discontinuous structure, which, in fact, does not exist as such, and disappears after suitable treatment. For this reason it has been called a phantom lamination, which the authors consider an appropriate term. It is the purpose of this paper to describe the phenomenon and the conditions of its occurrence and, at least tentatively, to discuss its nature and cause. Great numbers of phantoms may be found in 2:r brass, either hot-rolled or cold-rolled. They are also found in 70-30 brass, sometimes when hot-rolled and generally when cold-rolled. It is not believed that phantoms are confined to these alloys but this paper is limited to them for the purpose of description. Hot-rolled 2:1 Brass For illustration, therefore, a typical cake of hot-rolled 2:I brass has been chosen. This was rolled to a slab 36 in. thick, from a casting 5 in. thick by 24 in. wide by 18 in. high, which was believed to have been sound. After hot-rolling and cooling, the slab was sheared and a portion of such a shear cut is shown in Fig. I. It would be difficult to convince anyone viewing this specimen that the metal was not unsound. The impression would be confirmed by the appearance of a tensile break, as shown in Fig. 2. This is an ordinary tensile-test piece from metal just described. Although there was nothing in its tensile strength or elongation that suggested unsoundness, it appeared run through with pipes and laminations. To question the reality of such a condition would imply questioning the obvious. But, considering the history of the metal, it would be difficult to believe that it could be so bad as it appeared. It seemed reasonable, though, that if the defects were what they appeared to be, they could be traced back from the sheared or broken face.

Jan 1, 1945

By F. Weinberg, E. H. McLaren

Dilute binary alloys have been solidified under controlled thermal conditions, and solute distributions, temperatures during freezing and melting, and the position and morphology of the solid-liquid interfaces have been examined. Binary Zn, Sn, and Pb based alloys were investigated with solute additions of AgU°, AU°, Sb'24, TlZo4, snH3, and Zns5. Approximately 150 cc of metal was used in each ingot. Appreciable solute segregation occurred in most of the ingots, depending on the solute concentrations, distribution coefficients. and freezing conditions of the alloys. Measurements were made of the general solute distribution by sectioning layers of material from the ingot circumference and counting the activity of each layer. Local segregation was detected by autoradiographic techniques. Freezing and melting curves for the same alloys were obtained by precision resistance thermometry. These curves are related to the corresponding measured solute distribution curves and those calculated from theoretical expressions. The position and morphology of solid-liquid interfaces during freezing were determined by both decanting and quenching techniques. The results indicate the manner in which freezing and remelting occurred under the conditions investigated. If an isomorphous dilute binary alloy is solidified or melted under equilibrium conditions, the concentration of solute in both solid and liquid would be uniform at all stages in the freezing process. The solute concentrations during freezing could be determined from the phase diagram of the alloy, and the freezing curves would have an alloy slope defined by the solidus and liquidus points. In practice, however, solidification under equilibrium conditions rarely, if ever, occurs, primarily because of low rates of diffusion in the solid and incomplete mixing in the liquid. As a result, the solute distribution and the shape of the freezing and melting curves obtained in a given system depends on a number of factors. These include, in addition to the extent of diffusion and mixing, the initial solute distribution and concentration, the distribution coefficient, the rate of freezing or melting, supercooling of the liquid, the morphology of the solid-liquid interface, and the effect of annealing. The purpose of the present investigation was to determine, experimentally, actual solute distributions and thermal curves for a series of dilute binary alloys, using tracer techniques to determine the solute distributions and precision resistance thermometry for the temperature measurements. In addition, observations were made of the positions and morphologies of the solid-liquid interfaces during freezing and remelting. The distribution of solute in a dilute alloy, assuming complete mixing in the liquid, and negligible diffusion in the solid, is given by1 where Co is the mean solute concentration of the alloy, C, is the solute concentration in the solidg is the fraction of the ingot solidified, and ko is the equilibrium solute distribution coefficient (assumed to be independent of concentration for dilute alloys). For the case of partial mixing, ko can be replaced by an effective distribution coefficient k. If solute transport in the liquid is assumed to be entirely due to diffusion, with negligible diffusion in the solid, then the solute distribution in the solid is given by Tiller et a1.' as where R is the rate of advance of the solid-liquid interface, D is the solute diffusion coefficient in the liquid, and x is the position of the interface from the start of freezing. The temperature at the interface TI is related to the solute concentration of the solid at the interface C, by the expression where Tm is the freezing temperature of the pure solvent and ml is the slope of the liquidus for the binary alloy being considered. Accordingly, by relating TL to the actual temperatures measured in the present experiments, solute distributions can be deduced from the temperature measurements. Using the above expressions, the measured solute distribution of a given alloy may be compared to the theoretical distributions, as well as to the distribution calculated from the observed freezing curve. EXPERIMENTAL The solvent materials used in making up the binary alloys were C. P. New Jersey zinc (99.999 pct), Vulcan Extra Pure Tin (99.999 pet), and Tadanac lead (99.998 pct). The solute elements were of 99.99 pct purity or better, and were activated in the

Jan 1, 1963

By M. Muskat R. D. Wyckoff

The phenomenon called "water-coning" is that, observed in many oil wells, in which bottom water gradually and frequently sudderlly displaces a part or all of the oil production when a certain rather critical production rate from the well is exceeded. To follow in detail the process of the formation of a water cone as it breaks through the oil zone and enters the well bore is a problem so complex as to make a theoretical analysis practically impossible. However, an analytical treatment of the flow system before the water has broken through and during the time that it lies statically beneath the oil zone with an elevated or "coned" surface can be carried through under certain approximations. To present an analysis which shows the essential characteristics of the coning mechanism is the purpose of the present discussion. Physical Basis of Theory and Meaning of Approximations As will always be true for flow systems where true water-coning is at all possible, the water will be supposed to lie beneath the oil zone because of its density contrast with respect to the oil. In fact, tinder the usual field conditions, when the pay horizon is reasonably homogeneous, the water most frequently enters the well through the lower zones, but even when it enters from intermediate zones it may, in the later life of the well, displace the bottom layers of oil, thus resulting in a system wherein the oil is effectively floating on the water.

Jan 1, 1935

By John Blandy

EVERY new mining district has had its own peculiar experiences in inventing and experimenting upon new methods for the various operations of mining, and more particularly in the processes of crushing and dressing ores. As a matter of course, during this period many old things have been reinvented, patented, and cast aside, there to remain until at a future day other geniuses shall bring them forth again as new. In this respect the Copper Region of Michigan has not been behind other mining centres, and probably in no other part of the country has more money been expended in devising new machines and improvements upon old ones for the crushing of the rock. The appliances for washing the sand have not been so varied, simply for the reason that, having but one mineral, or rather metal, of high specific gravity to separate from rock material which varies but little in its character in any one mine, it requires much less care than is necessary in most mining centres of the world. At the beginning of operations in that district most of the work was in the control of Cornish miners, who introduced the simplest of Cornish mills, namely, wooden stem pestles, with wooden shafts and cams. These were well suited to the small mines, and particularly to the limited means of transporting more expensive machinery. As these facilities improved, they were enabled to change to iron, and to vary their patterns of rods, shafts, cams, and mortars. The most approved pattern, finally obtained, is the square or round stem, with collar adjustable by means of keys. In its present form it is a bar of cold rolled shafting, an eye in the top, an adjustable collar with key-plate and keys, the head and a shoe of chilled iron. The stem is fitted into the head by a slight taper. The battery has heretofore been of wood, lined with chilled cast plates, and bed-plate of the same, but within the past year the California pattern has been introduced. The screens are of sheet-steel, drilled with 16 holes to the inch. During this period of trial and gradual improvement in the pestle stamps, in the years 1855-6, the Ball steam-stamps were intro¬duced, and after years of labor and expense, have been made the most efficient and powerful machines ever yet used for the purpose. It is ostensibly the Nasmyth steam-hammer, and yet the

Jan 1, 1874

By R. J. Evans, A. G. Revesz

Silicon films have been grown by chemical reaction on (111) silicon substrates. The surfaces were examined by various microscopic and interfero-metric methods. Surface structures are classified into two groups depending on whether the angles between the bounding planes and the (111) surface are small (<3 deg) or large (> I0 deg). A layer-gvowth mechanism is postulated to explain the topography and the influence of growth parameters. Growth proceeds by lateral expansion of the (111) layers in (211) directions, thereby forming steps. The step edges are perpendicular to the direction of expansion and are thus along (110) directions. Step bunching md surface nucleation both play an important role in modifying the flow pattern and in the step regeneration. These are influenced ver?) much by impurities, especially oxygen. Although the growth is a result of a surface-controlled ga: reaction, it is very similar to growth from an impure solution. OVERGROWTH ("epitaxial growth") of silicon is important and widely used. During the past years several investigators have observed various topographical features or so-called faults on the grown films. A study of the surface morphology gives some insight into the growth mechanism. I) EXPERIMENTAL Silicon films have been grown on silicon substrates by a method described by Theuerer.&apos; Silicon is formed by reduction of SiCl, in hydrogen. The rate of incidence of SiC1, was varied between 5 x 10"6 and 2 x 10&apos;4 moles min-&apos; cm-&apos;. The mole fraction of Sic4 in the Hz-SiCL mixture was about 5 x X Both the rate of incidence and the mole fraction were calculated on the assumption that the Hz bubbling through the SiC1, reached equilibrium saturation. Assuming uniform velocity distribution, the linear velocity of the gas in the reactor tube was estimated to be 2 cm sec-l. The temperature of deposition was varied between 1070" and 1260°C. Chemically polished p-type silicon wafers of 20 to 100 ohm cm resistivity were used as substrates. These were within 1/2 deg of a (111) orientation. The thickness of the grown n-type film was determined by two methods: a) measurement of the depth of the p-n junction taking into account the junction shift due to diffusion, b) measurement of the traces of stacking-fault tetrahedra on the (111) plane.&apos; The agreement between the two methods was better than 20 pct. The rate of growth varied between 0.2 and 4.0 pmin-&apos;. The formed films were examined by reflection and light-section microscopy, and by multiple-beam interferometry. Phase-contrast illumination revealed height differences of about 30A. For measuring heights greater than 1 p a light-section microscope3 was used. The resolution by multipke-beam interferometry4 was between 50 and 100A. Crystallographic directions on the surface were determined by X-ray and from the orientation of etch pits and stacking faults as revealed by Dash etch (I part HI?, 3 parts HNOJ, and 12 parts CH3COOH). Some specimens have been investigated by electron microscopy. Platinum-shadowing and carbon-replica techniques were used to show the fine topography and reflection diffraction to determine the structure of the grown layers. 11) RESULTS The topographical features can be classified into three groups. he first group is comprised of fine ridges (striations). The second group consists of structures, which are bounded by planes making angles of less than 3 deg with the (111) surface. They are, therefore, vicinal planes. Structures which closely resemble growth or etch pyramids from the third group would normally be bounded by perfect low-index crystallographic planes. In this case they are deformed. The angles between the bounding planes and the (111) surface are generally larger than 10 deg. The fine ridges are present, even on the smoothest surfaces, as shown in Fig. 1. They are along a (110) direction. The height differences could not be resolved with interferometric techniques. The basic characteristic structures of the second group are depressions and hillocks. These are bounded by three planes, two of them with larger slopes than the third one. The edges between the planes, as projected to the (111) surface, point in (211) directions. Various habits of these structures are shown

Jan 1, 1964

By W. R. Crane

THE support of roof in mines is dependent largely on the character of the top rock and its occurrence. The formations overlying the orebed in the Birmingham district are sandstone and slate. The sandstone occurs in beds of sufficient thickness to constitute important elements in the system of support; the slate is relatively strong but is thinly stratified. The alternating beds of sandstone and slate furnish an excellent combination in that the former are strong and the latter are impervious; however, their continuity is broken by jointing or slip planes. The thickness, and consequent weight of the overlying formations, is important in so far as the size and arrangement of pillars are concerned but may be relatively unimportant, temporarily at least, as a factor in the support of the roof. The position of the respective beds of sandstone and slate, their relative thickness, and their inherent weakness because of the occurrence of faults and folds, may exert a predominating influence on their support in place, which is affected only in part by the weight of the cover. The only mine in this district that operates under a cover of approximately 2000 ft. (1900 ft.) is the Shannon so-called "twin slope," situated 14,000 ft. southeast of the portal of the No. 7 mine of the Tennessee Coal, Iron, & Railroad Co. The conditions in this mine indicate what may be expected in other mines when the same depth is attained; in fact the effect of pressure is shown in several mines that have not reached two-thirds of that depth. It is evident then that conditions affecting the support of roof will not improve but rather will become more difficult with the extension of the mines into the valley under a constantly increasing weight of cover. Further, the difficulties will probably be augmented by the occurrence of faults and other disturbed ground, the presence and position of which at present are largely unknown.

Jan 9, 1924

By B. L. Cusack, N. W. Stump

Selected technological developments applicable to lead and zinc mineral processing and changes in Australian concentration practices made since 1770 are reviewed. Laboratory and pilot plant studies of two new ores have been conducted since 1770. These have resulted in final flowsheet proposals which are described. New production capacity since IT0 has been based on plant expansion or the retreatment of oxidised tailings from plants operating pre-1940ts. Major developments in existing plants have come from the application of computer control to crushing, grinding and flotation and the installation of on-stream analysis systems. Flowsheet configurations have been altered in a number of plants. Selected research topics applicable to lead and zinc processing are also reviewed.

Jan 1, 1977

By Donald E. Cummings

Measures appropriate for the control of the silicosis hazard in mining cannot be formulated precisely, but sufficient knowledge1-l9 has accumulated during the past quarter century to permit the suggestion of useful, though partly empirical, rules for its alleviation. The industrial hygienist today recognizes that the peril incurred by the inhalation of harmful dust is a function of two variable factors—the degree of harmful exposure and the specific susceptibility of the exposed individual to pulmonary injury. Control of the danger arising out of prolonged contact with pernicious airborne particulate matter is consequently best exercised by influencing both of these recognized variables. Obviously the problem has two broad aspects—one, medical; the other within the province of the engineer. I—Factors Comprising Degree of Individual Susceptibility Thorough investigations conducted among miners who have labored for years in the presence of recognized silicosis hazards usually reveal an impressive difference in the injury incurred by men whose exposure to dust has been nearly identical. After a quarter century underground, one individual is short of breath and incapacitated with miners&apos; complaint, while a fellow workman suffers no pulmonary embarrassment and is in good health. Physicians ascribe this oft-observed difference in reaction to individual susceptibility and express a universal regret when they deplore the fate that chose to make the predisposed youth a miner rather than a farmer. To trust the health of miners to fate at the present time is even more unfortunate, because many of the factors that influence man&apos;s susceptibility to dust are known, and can be accurately determined by competent medical methods. Among the most important factors comprising susceptibility to injury by dust are the anatomical peculiarities of the individual&apos;s respiratory mechanism, his physiological response to the inhalation of dust, his previous dust, exposure, the existence of pulmonary infections or other pathological processes in his lungs, his age,

Jan 1, 1940

By Vaughn Moyer

A method for incorporating well drawdown effect into reservoir calculations is presented in detail, together with examples of its use for widely divergent conditions that could be normally encountered in oil reservoir sands. Tentative conclusions as to the effect such factors as permeability, producing interval, well spacing, or well damage caused by completion or repair practice could have upon economic ultimate recovery are reached. It is carefully pointed out that the conclusions reached are subject to limitations indicated in the text, and placed upon all calculations made in the paper. Introduction Papers have been presentedl-3 in which theoretical depletion histories for reservoirs under equilibrium conditions and no appreciable well-bore drawdown pressure are determined. However, except for a limited number of cases, appreciable drawdown Pressures in a well bore exist, and Pressure and saturation gradients consequently vary throughout a reservoir. This Paper is an attempt to incorporate well-pressure drawdown into reservoir history, and to analyze certain factors, such as those involving recovery, well spacing, and productivity index, from the standpoint of permeability and drainage radius. BY incorporation of drawdown into reservoir history, it is believed that theoretical considerations will more closely approxi- mate actual reservoir behavior experienced in an oil field. For purposes of simplification, a solution gas-drive type field1 without primary gas cap, has been selected. Basic Data and Assumptions Details of equilibrium saturation conditions for no drawdown production for various pressures in a reservoir are deter-minable by methods described by several are permitting the construction of a curve of oil saturation vs Pressure for any selected combination of initial interstitial water and hydrocarbon saturation (Fig I). This curve is then a description of equilibrium saturation conditions at any given pressure in a reservoir. Developing the above, details of saturation and flow permeability may thus be determined for any increment or portion of a well drainage area or reservoir. In this manner the effect of pressure differential (drawdown) may be incorporated into reservoir and well drainage considerations. It is pointed out that this method thus makes use of no-drawdown equilibrium production data, superimposing a draw-hwn effect upon them. It also assumes that net flow conditions in any considered increment of reservoir are not materially altered by the entrance of fluids from other increments into them, but approach equilibrium for the existing pressure and saturation (i.e., each increment behaves in more or less independent fashion, dependent largely upon the equilibrium considerations mentioned above)

Jan 1, 1948

By Vaughn Moyer

A method for incorporating well drawdown effect into reservoir calculations is presented in detail, together with examples of its use for widely divergent conditions that could be normally encountered in oil reservoir sands. Tentative conclusions as to the effect such factors as permeability, producing interval, well spacing, or well damage caused by completion or repair practice could have upon economic ultimate recovery are reached. It is carefully pointed out that the conclusions reached are subject to limitations indicated in the text, and placed upon all calculations made in the paper. Introduction Papers have been presentedl-3 in which theoretical depletion histories for reservoirs under equilibrium conditions and no appreciable well-bore drawdown pressure are determined. However, except for a limited number of cases, appreciable drawdown Pressures in a well bore exist, and Pressure and saturation gradients consequently vary throughout a reservoir. This Paper is an attempt to incorporate well-pressure drawdown into reservoir history, and to analyze certain factors, such as those involving recovery, well spacing, and productivity index, from the standpoint of permeability and drainage radius. BY incorporation of drawdown into reservoir history, it is believed that theoretical considerations will more closely approxi- mate actual reservoir behavior experienced in an oil field. For purposes of simplification, a solution gas-drive type field1 without primary gas cap, has been selected. Basic Data and Assumptions Details of equilibrium saturation conditions for no drawdown production for various pressures in a reservoir are deter-minable by methods described by several are permitting the construction of a curve of oil saturation vs Pressure for any selected combination of initial interstitial water and hydrocarbon saturation (Fig I). This curve is then a description of equilibrium saturation conditions at any given pressure in a reservoir. Developing the above, details of saturation and flow permeability may thus be determined for any increment or portion of a well drainage area or reservoir. In this manner the effect of pressure differential (drawdown) may be incorporated into reservoir and well drainage considerations. It is pointed out that this method thus makes use of no-drawdown equilibrium production data, superimposing a draw-hwn effect upon them. It also assumes that net flow conditions in any considered increment of reservoir are not materially altered by the entrance of fluids from other increments into them, but approach equilibrium for the existing pressure and saturation (i.e., each increment behaves in more or less independent fashion, dependent largely upon the equilibrium considerations mentioned above)

Jan 1, 1948

By Donald E. Cummings

Measures appropriate for the control of the silicosis hazard in mining cannot be formulated precisely, but sufficient knowledge1-l9 has accumulated during the past quarter century to permit the suggestion of useful, though partly empirical, rules for its alleviation. The industrial hygienist today recognizes that the peril incurred by the inhalation of harmful dust is a function of two variable factors—the degree of harmful exposure and the specific susceptibility of the exposed individual to pulmonary injury. Control of the danger arising out of prolonged contact with pernicious airborne particulate matter is consequently best exercised by influencing both of these recognized variables. Obviously the problem has two broad aspects—one, medical; the other within the province of the engineer. I—Factors Comprising Degree of Individual Susceptibility Thorough investigations conducted among miners who have labored for years in the presence of recognized silicosis hazards usually reveal an impressive difference in the injury incurred by men whose exposure to dust has been nearly identical. After a quarter century underground, one individual is short of breath and incapacitated with miners&apos; complaint, while a fellow workman suffers no pulmonary embarrassment and is in good health. Physicians ascribe this oft-observed difference in reaction to individual susceptibility and express a universal regret when they deplore the fate that chose to make the predisposed youth a miner rather than a farmer. To trust the health of miners to fate at the present time is even more unfortunate, because many of the factors that influence man&apos;s susceptibility to dust are known, and can be accurately determined by competent medical methods. Among the most important factors comprising susceptibility to injury by dust are the anatomical peculiarities of the individual&apos;s respiratory mechanism, his physiological response to the inhalation of dust, his previous dust, exposure, the existence of pulmonary infections or other pathological processes in his lungs, his age,

Jan 1, 1940

By J. M. Smith, D. Kunii, P. Adivarahan

Effective thermal conductivities were measured for seven samples of porous rocks through which gases or aqueous salt solution were flowing, parallel and countercurrent to the flow of heat. The results are analyzed in terms of the contributions of the solid and fluid phases to the total energy transfer. The solid contribution for the sandstone samples studied was found to be a Junction of the porosity and an effective thermal conductivity for the solid phase. The fluid contribution was a function of the Peclet number. Based upon the equations presented, the effective conductivity of the system can be estimated from the properties of the fluid, the flow conditions, and the porosity and pore-size distribution of the rock. INTRODUCTION Heat-transfer characteristics of porous media containing fluids are needed for the design and evaluation of thermal methods of petroleum production. The study reported here considers the problem of countercurrent flow of fluid and heat in sandstone rocks, and is a continuation of previous studies concerned with parallel and radial flow of energy and fluid in both rocks517 and beds of fine particles.6,10 In addition to these earlier works, Asaad,1 Kimura,4 Preston,8 Zierfuss and vlietll and waddams9 have reported effective conductivities for systems filled with stagnant fluids. There appears to be no published data on rocks through which fluids are flowing. The purpose of this study was to present such information and, particularly, to investigate the effects of properties of the rock and the flow rate on the results. The rock samples were naturally occurring sandstones from different locations and were similar to petroleum-bearing formations. The properties of the seven samples showing the range in porosities and permeabilities are given in Table 1. The mean pore sizes were calculated from mercury penetration data by averaging the radius with respect to pore volume. The details of this method and comparison with other procedures for estimating 7 are given elsewhere. Four fluids, nitrogen, carbon dioxide, helium and 10 weight per cent sodium-chloride solution were used with each sample. For Bartlesville sandstone, BA-5, runs were made at mean pressures from 15 to 250 psig using nitrogen. The other measurements were carried out at a mean pressure of 100 psig. The maximum temperature range eacountered was 70° to 300°F. The flow rate of fluid ranged from about 1.0 to 130 Ib/(hr)(sq ft), and this corresponded to a modified Reynolds-number range of 5 x 10-4 to 1.0. The variation in Prandtl number was 0.70 to 4.1. EXPERIMENTAL WORK The equipment consisted of apparatus to supply a constant flow of gas, or salt solution, at constant pressure to the bottom of a vertical test section, and metering and flow-regulation apparatus after the test section. The flow of salt solution was

By W. Spencer Hutchinson

The experiments described in this paper were undertaken primarily for the purpose of measuring the quality of work done in screening and sorting in American concentrating-mills for Prof. Richards&apos; work on Ore-Dressiag. For this purpose a series of samples of screened and sorted products was obtained from four different mills, and a plan was devised for sizing these products, and for tabular and graphic representation of the results. The results, together with discussions as to their significance, so far as they serve to interpret the quality of mill-work, have already been published in the above-mentioned work, and it is not the purpose of this paper to duplicate the work, except so far as is necessary to explain and illustrate methods and appliances. The sizing of coarse products was clone by sifting on screens of sheet-metal with round punched holes. These holes ranged in size from 64 mm. to 0.5 mm. in diameter. Below the smaller limit, punched metal, suitable for this work, was not obtainable, and the sizing was carried on by sifting on woven wire-sieves. The finest woven wire-cloth obtainable gave a hole 0.073 mm. square, and the finest silk bolting-cloth pave a pentagonal hole with an average diameter of 0.069 mm. Even these very fine screens served no useful purpose in sifting certain of the very fine classifier-products, of which all, or nearly all, passed through the finest screen. A new adaptation of a method of settling and decantation with water in beakers was therefore worked out, and by this means the sizing mas carried down to grains of a diameter as small as 0.012 mm. Description of Apparatus and Manipu1ntion.—Sieves of sheet-metal with round punched holes were used as far as practicable, chiefly because, as already explained, the primary object of the experiments was to test mill-work, and the mills had all used

Jan 1, 1905

By Nicasio del Castillo

INTRODUCTION The tax structure of foreign mining investment into the United States has a significant impact on the financing and the profitability of the operation. For these reasons, it is critical for the foreign investor to develop and implement a well planned tax strategy that will enable its venture to: (1) reduce its U.S. income tax liability (2) lower U.S. withholding taxes when funds are transferred from the United States, and (3) decrease or defer home country taxation on its U.S. earnings ALTERNATIVE FORMS OF INVESTMENT A threshold business and tax consideration is the form in which the investment is to be made. The most common alternatives include: forming or acquiring a U.S. mining corporation, directly establishing a branch mining operation, or entering into a joint venture or partnership with a U.S. mining company. U.S. Corporations The most common structure through which foreign mining companies engage in business in the United States is to form a U.S. mining corporation. Forming a U.S. Corporation. If the investor decides to establish a new U.S. corporation the organization is relatively simple. No distinctions are made in the United States between "public" and "private" forms of incorporation. Minimum share capital is not usually required and share capital may consist of shares with no par value. Since corporate law is the responsibility of the individual states, the foreign investor must choose a state in which to incorporate. If appreciated mining property is transferred to a corporation solely in exchange for stock or securities in that corporation, and the transferors have control of the corporation (defined as at least 80 percent of all voting shares and at least 80 percent of all other shares) immediately after the exchange, no gain or loss will be recognized. However, if the transferors receive cash or other mining properties in addition to stock, any resulting gain may, in certain situations, be taxed to the extent of the cash and the fair market value of other property received. Acquiring an Existing U.S. Corporation. Acquiring an existing U.S. mining corporation is not as straight-forward as forming a corporation. This alternative may be accomplished through either a stock or an asset acquisition. Generally, with a stock acquisition the purchaser inherits all of the business and tax attributes of the former mining corporation. If the investor is able to acquire mining assets, however, the purchaser will usually be able to avoid any unknown or hidden liabilities that could be attached to an existing corporation. Another principal advantage in acquiring assets is that the purchase price may be directly allocated to the acquired mines or other mineral-related assets with the result that the assets&apos; depreciable base may be increased. Assuming the domestic seller and the foreign purchaser can agree, it is generally advisable to allocate the purchase price in the sales agreement to specific individual assets. From the foreign investor&apos;s standpoint, it is preferable to allocate the purchase price to depreciable assets such as buildings and equipment versus an allocation to mineral land holdings or intangibles such as goodwill, which are generally not depreciable. It is not uncommon, however, for a seller mining company being acquired to insist for tax reasons that the investor purchase shares rather than assets. If the foreign

Jan 1, 1985

By C. D. Dolman

SINCE the outbreak of the war we have discovered in the United States minerals of which there was no general knowledge, and which compared very favorably with anything that could be found in any foreign country. One of these was magnesite, or the carbonate of magnesium as it occurs in nature. This mineral crystallizes in the rhombohedral form, has a specific gravity of 3.00, molecular weight of 84 4, molecular volume of 28.1, and a hardness of 3.5 to 4.5.1 Had it not been for the development of the California deposits of this mineral and the discovery of immense new deposits in Stevens County, Wash., the production of steel during the war would have been more seriously handicapped than it was. Now, that the war is over, we face the possibility of competition&apos; with the cheap Austro-Hungarian magnesite; and while that may not he so cheap as it was before the war, adequate protection should be given the producers in this country to insure the full development of our own resources. The consumption of magnesite in the United States in 1913, the year preceding the war, was 172,591 tons of calcined and 22,872 tons of crude magnesite. Less than 3 per cent. of this amount was produced at home. At the present time, practically all of the magnesite used in the United States is produced at home. Expensive plants have been constructed, extensive exploration work done, and production pushed to the utmost to supply the necessary requirements of the war. Thus a considerable industry has been built up within our borders. Some magnesite has been imported from Canada and Mexico, but the Canadian ore was of an inferior grade and could not be used satisfactorily. During the year 1918, production decreased in both the United States and Canada; the production in the United States was 225,000 tons in 1918 as against 315,000 in 1917, and in Canada 39,365 tons in 1918 as against 58,090 in 1917.

Jan 8, 1919

PROGRESS IN DRILLING tungsten-carbide bits, lighter pneumatic drills, bonus plans, and alloy steels are discussed at northwestern gathering.

Jan 3, 1951

SAN FRANCISCO SECTION W. H. SHOCKLEY, Chairman, PRANK H. PROBERT, Vice-Chairman, T. A. RICHARD, Sec.-Treas., 420 Market St., San Francisco, Cal. C. C. BRAYTON, J. F. NEWSOM. The San Francisco Section met on September 11 to discuss the problem of Labor in its Relation to the Mining Engineer. Mr. W. H. Shockley was in the chair. T. A. Rickard opened the discussion under four heads: The recognition of the union, the rustling-card, the sliding scale of wages, and the&apos; contract system. He expressed his belief that collective bargaining cannot be ignored, and insisted that the mining company represented a collective bargaining of its shareholders with the men. employed in its mine. He held that the contract system was often used unfairly, but that used fairly it was the best check on labor tyranny. The rustling-card he held to be right in principle, in so far as it gave the employer the choice of employees, but he believed that it was often used in an irritating way to black-list refractory laborers. The sliding scale of wages was easy to establish in prosperous times, but it would inevitably lead to trouble when conditions went against the miner. His conclusion was that the quarrels of labor and capital were due mainly to a lack of the sense of fair play and of social justice. Albert Burch agreed with most of the foregoing, and insisted that 90 per cent. of the men were inclined to be just, but that the 10 per cent: made all the trouble. He stated that he had introduced the rustling-card in the Coeur d&apos;Alene in 1899, as a means for getting rid of agitators. E. L. Foucar considered that labor was irresponsible. He described his experience in Peru, where the authorities promptly stopped a strike of Italian miners by threatening prompt punishment for any display of violence. Morton Webber also gave a bit of his own experience, to show that the chief trouble is that the men do not think for themselves, and are therefore easily led by fomenters of trouble. F. H. Probert described his experiences in Germany and. also in Arizona, and insisted that too often the men were not given a fair hearing. E. T. Blake argued that a manager must get the workmen&apos;s point of view, in order to control them effectively. He believed that young men who started life doing manual labor were in a better position to understand their fellow workers. George J. Young suggested that the mine owners should encourage the good men to lead the unions, and not leave the direction of the unions to the noisy element.

Jan 12, 1917

By R. W. Guard

ALTHOUGH etching techniques have been developed for revealing dislocation sites in several metals and ionic crystals,h t is valuable to extend the technique to new metals. An etch pit method for nickel has been developed on the basis some suggestions of Dr. John R. Cuthill of the National Bureau of Standards who had observed etch pits in creep specimens of nickel. The etchant used was proposed first by wensch2 for revealing grain size in nickel. The present paper describes the evidence that the technique can be used to reveal dislocations and gives the conditions under which etching can be carried out. The specimens examined were vacuum melted high-purity Ni (99.985 pct Ni) and commercial "A" nickel (99.8 pct Ni). Both materials contained greater than 0.008 pet C and had been annealed in nitrogen or dry hydrogen at 1100o to 1200°C. This gave a grain size of 1.5 mm in the high-purity nickel and 0.050 mm in "A" nickel. Tensile specimens (0.254 in. diam) were deformed from 0.25 to 10 pct at room temperature and then heated for 1/2 hr at different temperatures from 400" to 900°C. The specimens were sectioned longitudinally then polished electrolytically in 60 pct H2SO4 and etched in 35 pct H3PO4 solution at 0.2 to 0.4 v for 30 sec to 3 min. The best method for setting the proper voltage for etching is to increase the voltage until gas bubbles are evolved vigorously from the specimen and then cut it back by 10 pct. It is necessary to heat the specimen above 500°C after deformation in order that etch pits will be formed. This "decoration" treatment permits carbon to segregate to the dislocation rendering them sensitive to etching. It was demonstrated that carbon was the decorating impurity by decarburizing some specimens in wet H2 at 1200°C. The susceptibility to etch pitting was lost following this treatment but could be restored by carburizing in contact with graphite. Some rearrangement of the dislocations in the as-deformed structure occurs on heating at 500oC and above so that the technique can not be used to study the nature of dislocation patterns in deformed specimens. Extended etching does not change the number of pits although the background becomes rough and the pits quite large. The polycrystalline specimens with various strains were examined after annealing at different temperatures. Typical patterns are shown in Figs. 1 and 2. In the unstrained specimen, Fig. 1, the density of pits is 2.5 X 10&apos; per sq cm. All grains show pits regardless of their orientation although there is a

Jan 1, 1961

By R. D. Satterley

THE Sherwood mine is an iron-ore mine owned and operated by the Inland Steel Co. in the Iron River district of the Menominee Range in Michigan. The property consists of an 80-acre tract in the village of Mineral Hills, about a mile north of the city of Iron River. The ore mined is a reddish brown, nonbessemer hematite and limonite. The ore bodies lie in a large syncline having an east-west strike and are associated with a rock structure that is folded in a complex manner. The two 40-acre tracts run north and south and the shaft is at about the center of the north forty. The shaft is 1286 ft. deep, with the principal operating level at a depth of 1000 ft. from surface. A new level at a depth of 1200 ft. is in process of development. The ore body at the 1000 ft. level is east and west at approximately the line between the north and south forties and at this elevation is from 50 to 250 ft. wide and extends above the level at varying heights of from 50 to 250 feet. The 1000-ft. haulage drift extends south from the shaft, through the east-west ore body to the slates on the south side of the body. The ore body was intercepted in the drifting at about 800 ft. from the shaft and was about 200 ft. wide at that point. A crosscut was extended to the east and west property lines along the south boundary of the ore body. This east-west ore body is laid out in areas 80 ft. wide for stoping with pillars 40 ft. wide. With this plan a stope is approximately 80 by 200 ft. and has a pillar on both sides that is approximately 40 by 200 ft. The ore has a height of from 50 to 250 ft. above the elevation of the level, therefore the height of the stopes varies in accordance with the height of the ore body at each location. From the crosscut, two main raises, each 6 by 7 ft., are put up into each 80 ft. stope area (Fig. I). One of the main raises serves as a manway and the other as an ore raise, through which the ore is transferred from the stope to the tramming equipment. The original layout was for scraping of the ore from under the stopes into the ore raises. The ore raise is put halfway (east and west) along the 80-ft. stope area and usually is in iron formation. The manway and ore raise are on approximately 15-ft- centers. These main raises are put up to a height of from 22 to 30 ft. above the level floor, then from the top of the ore raise a scraper drift (8 X 8 ft.) is driven across the width of the ore body, which is in the neighborhood of 200 ft. From the scraper drift, mill raises are put up at 12 ½ -ft. centers, staggered on opposite sides of the drift, and these are extended 23 ft. above the elevation of the scraper-drift floor. The sublevel connecting the top of these mill raises is called a mill "sub." Other sublevels are developed parallel to the scraper and mill subs at 25-ft. vertical intervals above the mill sub. The mill sub and the other subs above the mill sub are known as sublevels or dog drifts, and are 4 ft. wide and 6 ft. high. These dog drifts

Jan 1, 1945

By K. B. Nowels

The attainment of efficient flooding to a large extent depends upon a knowledge of fluid movement through porous media and the pressures used in controlling this movement. Little has been understood con-cerning the fundamental principles involved in the forced drive of water-flooding and an attempt will be made to present some data which may be of interest. Considerable data and technical information pertaining to natural and artificial water-flooding have been presented in the past by Torrey, Umpleby, Fettke, Panyity and others. Their papers have thoroughly covered the description of past and present-day methods of oil recovery by flooding in the Bradford field, especially an article by Torreyl in the Petroleum Engineering Handbook. A bibliography of papers devoted to watcr-flooding, published in Mr. Torrey&apos;s article, is appended to this paper. No attempt has been made, therefore, to describe the installations and procedure necessary in flooding, thus permitting the writer to deal exclusively with the mechanics of water movement in flooding operations and its relationship to well spacing. Artificial water-flooding will probably always be the most successful in oil fields described by Herold as being under "capillary control"" and will probably be useless in fields naturally under hydraulic or volumetric control. The natural water drive in an oil field under either of these two controls may give efficient recoveries, as a result of the regulated encroachment of edge water. Such a "natural flood" resulting from the influence of edge water must not be confused with the term as used in this paper, however. Any reference to "natural flood" will here refer to the old method of flooding formerly used in the Bradford field. This was discovered largely by accident and utilized the hydrostatic pressure created by a column of water standing in a watered-out oil well in forcing the oil to an adjacent producing well. The same principles are involved in either natural or artificial flooding, and the latter method simply

Jan 1, 1933